This invention relates to locking mechanisms, and more particularly to gang locking mechanisms for cabinets of the type including a plurality of slidably mounted drawers.
Various forms of cabinet structures are known which include a plurality of vertically stacked, slidably mounted drawers. The drawers may be of different dimensions to provide bulk storage space, file folder storage space, stationary storage, etc. It is considered advantageous with such cabinet/drawer arrangement to provide a single key-operated lock serving, to lock all of the drawers in a closed position.
Heretofore, such drawer gang locking mechanisms have generally employed vertically extending lock bars which through a linkage or control rod arrangement are moved in a vertical direction or are pivoted upon actuation of a key-operated master lock. Each lock bar includes some type of latch or stop arrangement cooperating with each drawer to positively retain them in a closed position. The master lock is typically located at the top or on the side of the cabinet itself. The lock bars and linkage have generally been located along the forward or front panel of the cabinet to make the linkage mechanism less complex. As a result, it is possible to reach the operative portions of the gang locking mechanism with a screwdriver or other thin rod-like tool, and thereby override the locking mechanism. This is particularly true with the master lock mounted on the cabinet since one can insert the tool between the drawer and cabinet opening edge and force the linkage laterally or upwardly to pivot or raise the lock bar.
The U.S. patent to Zottel, U.S. Pat. No. 2,225,243, entitled "DESK" and issued Dec. 17, 1940 is an attempt to obviate this drawback by mounting the master lock and linkage in the drawer and provide for a linkage that extends to the rear of the drawer so that the lock bars are at the rear of the cabinet. Unfortunately, Zottel requires a separate linkage for each side of the drawer, where a lock bar is provided at each side of the master lock drawer. Also, Zottel could not coordinate the bell crank linkage with a pivot type lock bar and had to use vertical movement lock bars.
With all such systems employing a vertical movement lock bar or latch mechanisms which must be lifted for operation, a relatively high key rotational force is present. As the number of drawers and the overall height of the cabinet increases, the length, and therefore the weight, of the lock bar increases. An operator must lift this weight through rotation of the key in the master lock. Therefore, as the size of the cabinet increases, the key rotation force must necessarily also increase.
With the gang locking systems of the type exemplified by the above-referenced U.S. Patent and with various other forms of gang locking arrangements which employ a plurality of control rods, linkage members and latch bars or spring loaded latches, the overall arrangement is relatively complex, may be subject to jamming, and due to the number of components involved, may result in installation difficulties.